Improvement in claw-bars



UNITED STATES PATENT DFFIGE. I

W ALTER S. TERHUNE, RIDGEVVOOD, N. J ASSIGNOR OF ONE-FOURTH 7 OF HISRIGHT TO THOMAS ALDRIDGE WESTON, OF SAME PLACE.

IMPROVEMENT IN CLAW-BARS.

Specification forming part of Letters Patent No. 137,333, dated April 1,1873; application. filed June 7, 1872.

To all whom it may concern: I

Be it known that I, WALTER S. TERHUNE, of Ridgewood, in the county ofBergen and State of New Jersey, have invented an Improvement inOlawBars, of which the followin g is a specification:

My invention consists in a sliding fulcrumblock dovetailed in a groovein the heel of the bar, both the block and the groove being providedwith corresponding segmental proximate bearing-surfaces, as hereinafterdescribed.

In the drawing, Figure 1 is a perspective view of my improved pinch-bar,shown also in changed position by broken lines. Fig. 2 is an elevation,showing the slotted portion of the bar in section. Fig. 3 is aperspective view of the segmental fulcrum-block removed. Figs. 4 and 5are sections across the heel of the bar and block, showing equivalentmechanical devices for securing the latter in its seat.

I form the heel of the bar A with a longitudinal recess or groove, b,the bed of which is of segmental or convex form, as shown, into which Ifit a block, 0, the upper surface of which is concave, correspondingwith the convex part of the groove, the length of the block being onlyabout one-half of that of the groove to admit of the bar having asliding motion with relation to the block when used, the lat terremaining stationary. The block is formed with dovetailed sides, asshown in Fig. 4, and the sides of the groove swaged to it so as to forma loose fit, which will admit of the free movement of one part withrespect to the other, and yet prevent the bloc}: from becomingdisengaged when the bar is handled.

The operation is as follows: When the bar is applied to use for theraising of a body the elevation of its opposite end brings the point insuch position that the block 0 occupies the forward part of the grooveb. As the body is raised the convex bearing rolls within the concaveface of the block, which remains a stationary bearing, the heel of thebar sliding meanwhile and increasing the length of the short arm of thelever, thus raising the load higher and quicker than with a stationaryfulcrum.

I am aware that fulcrunrblocks have been pivoted to the heel of pinch orcrow bars by a fixed axis, but this does not produce the result obtainedby a movable or sliding fulcrum nor do I claim the devices set forth inLetters Patent'No. 78,669 of June 9, 1868; but

I claim as-my invention- The segmental sliding fulcrum-block G, incombination with the convex-faced groove b b in the heel of the bar A,all constructed as herein shown, for the purpose set forth.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

WALTER S. TERHUNE.

WVitnesses J. H. BLAUVELT, J. J. Kmnsrnn.

